Indicator material

ABSTRACT

The present invention is concerned with an indicator material which is obtained by impregnating a non-woven fabric, of which one surface is provided with a resin layer having a partly or wholly colored surface, with a volatile oily substance used as an active ingredient in a deodorant, an aromatic agent, an anti-fungal agent or a mothproofing agent, and which is used for showing the degree of dissipation of the oily substance which occurs with the passage of time, based on the shifting of the resin layer observable from the non-woven fabric side from a visible state to a state masked by the non-woven fabric, the indicator material overcoming a failure of conventional indicator materials containing non-woven fabrics in relatively clearly showing the degree of the oily substance with the passage of time, by using a non-woven fabric containing a fine-denier fiber having a size of 2 denier or less or by using a non-woven fabric having a partly altered density.

TECHNICAL FIELD

The present invention relates to an indicator material for indicatingthe degree of dissipation of a volatile oily substance which occurs withthe passage of time, the volatile oily substance being contained, anactive ingredient, in a deodorant, an aromatic agent, an anti-fungalagent, an insecticide, a mothproofing agent, and the like. Inparticular, it relates to an indicator material which is prepared byimpregnating a non-woven fabric with the above oily substance and whichindicates the degree of such a dissipation of the above oily substanceas occurs with the passage of time.

TECHNICAL BACKGROUND

The deodorant, aromatic agent, anti-fungal agent, insecticide,mothproofing agent, and the like, which are prepared by providing oilysubstances having volatility at room temperature or an increasedtemperature as active ingredients and impregnating predeterminedcarriers with the active ingredients, have been and are used assubstitutes for conventional articles containing volatile gels or solidsas active ingredients. Most of the above oily substances are odorless,and when they are used by impregnating carriers with the above odorlessoily substances, it is difficult to ascertain even the time ofexpiration thereof, not to mention the remaining content thereof, by thehuman sense of smell. For this reason, there have been developed avariety of indicator materials which can visually show users theremaining time and the expiration time of the oily substances.

Among the above indicator materials are the following two indicatormaterials each of which is prepared by impregnating a non-woven fabricwith the above oily substance and can visually show users the degree ofthe dissipation thereof which occurs with the passage of time.

One is a mothproofing material which also works as a mothproofingcapability indicator, in which one surface of an oil-permeablepaper-like material (including a non-woven fabric), which is alteredinto transparency when an oil (oily substance) is contained, is used asan indicating surface, an oil-impermeable pattern layer is formed on theentirety or part of the other surface of the paper-like material toobtain a substrate and the substrate is impregnated with an oilmothproofing agent volatile at room temperature (JP-B-4-36122).

In the above mothproofing material which also works as a mothproofingcapability indicator, since the paper-like material is altered intotransparency when an oil mothproofing agent is contained, the patternlayer provided on the other side can be visually observed. On the otherhand, since the paper-like material is gradually brought into anoriginal non-transparent state with the dissipation of the liquid oil,the pattern layer formed on the other side gradually becomes visuallynon-observable. Depending upon the pattern layer visually observablefrom the paper-like material side, therefore, users can visually knowthe degree of dissipation of the liquid oil (mothproofing chemical)which occurs with the passage of time.

The other one is a time length indicator prepared by consecutivelyapplying a colorant, which is altered into transparency when a liquidvolatile at room temperature penetrates it, to portions where the abovecontained liquid is dissipated earlier and later on the surface of asubstrate sheet (including a non-woven fabric) into which a liquidcontaining the liquid volatile at room temperature is penetrable, suchthat the colorant form layers as time length indicating layers (JapaneseLaid-open Utility Model Publication No. 5-14983). The above time lengthindicator uses the fact that when the substrate sheet containing theliquid volatile at room temperature is held horizontally, the liquidvolatile at room temperature is easily successively dissipated from anedge portion of the substrate sheet surface and that when the substratesheet containing the liquid volatile at room temperature is heldvertically, the liquid volatile at room temperature is easilysuccessively dissipated from the top of the substrate sheet. The timelength indicator having a predetermined form is provided depending upona pre-determined method of setting the time length indicator.

When the liquid is contained in the substrate sheet of the above timelength indicator, the time length indicating layers show a transparentstate, since the liquid penetrate the time length indicating layers.With the dissipation of the liquid contained in the substrate sheet, theamount of the liquid which has penetrated the time length indicatinglayers decreases, and the time length indicating layers accordinglybecome visually observable. Users can therefore know the degree of thedissipation of the liquid which occurs with the passage of timedepending upon which time length indicating layer can be visuallyobserved.

When a conventional non-woven fabric is impregnated with an oilysubstance volatile at room temperature or an increased temperature, thedissipation of the oily substance from the non-woven fabric does nottake place uniformly. Therefore, when a conventional non-woven fabric isused as a paper-like material to prepare an indicator material havingthe same constitution as that of the above mothproofing material whichalso works as a mothproofing capability indicator, the pattern layerformed on the other side of the paper-like material becomes visuallynon-observable with the dissipation of the oily substance, while thevisual sight thereof differs from one place to another on the paper-likematerial (non-woven fabric) and a spots-like pattern is observed. It istherefore difficult to clearly show the degree of dissipation of theoily substance which occurs with the passage of time with the aboveindicator material.

Further, a conventional non-woven fabric has the relatively low capacityto support the oily substance. That is, when the non-woven fabric isimpregnated with the oily substance in an amount equivalent to, orsmaller than, the volume of pores of the non-woven fabric, the capacityof the non-woven fabric to support the oily substance such that the oilysubstance does not seep is relatively low. Therefore, when aconventional non-woven fabric is used to prepare an indicator materialhaving the same constitution as that of the above mothproofing materialwhich also works as a mothproofing capability indicator, the indicatormaterial can contain only a relatively small amount of the oilysubstance.

On the other hand, a conventional non-woven fabric is used as asubstrate sheet to prepare an indicator material having the sameconstitution as that of the above time length indicator, the time lengthindicator layers do not relatively clearly show the degree ofdissipation of the oily substance which occurs with the passage of time.Further, this indicator material can contain only a small amount of theoily substance. Moreover, when the indicator material is set by a methodwhich is not predetermined when it is prepared, for example, when it isset slantly or upside down, the time length indicating layer showing atime length different from the time length which has actually passed isvisually observed, and the setting site and the setting method aretherefore limited.

It is an object of the present invention to provide an indicatormaterial which can clearly indicate not only the time of expiration ofthe oily substance but also the degree of dissipation of the oilysubstance which occurs with the passage of time, regardless of a settingsite and a setting method.

DISCLOSURE OF THE INVENTION

The indicator material for achieving the above object, provided by thepresent invention, is provided by forming a resin layer having a surfacepartly or wholly colored on one surface of a support formed of anon-woven fabric containing a fine-denier fiber having a size of 2denier or less, said support having a low refractive index to light, andimpregnating the support with an oily substance volatile at roomtemperature or increased temperature, characterized in that the resinlayer observed from the support side is shifted from a visible state toa support-masked state by the dissipation of the oily substance whichoccurs with the passage of time (the above indicator material will bereferred to as "indicator material I" hereinafter).

Another indicator material for achieving the above object, provided bythe present invention, is provided by forming a resin layer having asurface partly or wholly colored on one surface of a support formed of anon-woven fabric having a partly altered density and having a lowrefractive index to light, and impregnating the support with an oilysubstance volatile at room temperature or increased temperature,characterized in that the resin layer observed from the support side isshifted from a visible state to a support-masked state by thedissipation of the oily substance which occurs with the passage of time(the above indicator material will be referred to as "indicator materialII" hereinafter).

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic perspective view of a non-woven fabric-resinlaminate prepared in Example 30.

FIG. 2 is a schematic perspective view of an indicator material IIprepared in Example 30.

FIG. 3 is a perspective view which schematically shows a partialdiscoloration state on the indicator material II prepared in Example 30at a time of its use.

FIG. 4 is a schematic perspective view of an indicator material IIprepared in Example 35.

FIG. 5 is a schematic cross-sectional view of a preferred embodiment ofan indicator material I.

FIG. 6 is a schematic cross-sectional view of another preferredembodiment of an indicator material I.

PREFERRED EMBODIMENTS OF THE INVENTION

As schematically shown in FIG. 5, the indicator material I of thepresent invention is a material prepared by forming a resin layer 22having a surface partly or wholly colored on one surface of a support 21which is formed of a non-woven fabric containing a fine-denier fiberhaving a size of 2 denier or less and has a low refractive index tolight and impregnating the support 21 with an oily substance (not shown)volatile at room temperature or increased temperature. The term"non-woven fabric having a low refractive index to light" means that afiber constituting the above non-woven fabric has a low refractiveindex, and the refractive index value is preferably 2.0 or less, morepreferably 1.7 or less.

The non-woven fabric can be that which is basically non-transparent butsubstantially becomes transparent when impregnated with an oilysubstance volatile at room temperature or increased temperature, to bedescribed later, so that a color of the resin layer (color of a coloredportion) provided on one surface of the above non-woven fabric can beeasily observed from the non-woven fabric side. The refractive index ofa fiber constituting the above non-woven fabric is preferably similar tothe refractive index of the oily substance to be used for theimpregnation, while the non-woven fabric may contain a substantiallynon-transparent fiber so long as the non-woven fabric as a whole becomestransparent when it is impregnated with the oily substance.

The reason for limiting the non-woven fabric as a support to the"non-woven fabric containing a fine-denier fiber" having a size of 2denier or less" is as follows. That is, when the non-woven fabric isconstituted of a fiber having a size of more than 2 denier, the fiberhas a low capacity to support the oily substance among its filaments,and the oily substance is therefore liable to leak even if the non-wovenfabric is impregnated with the oily substance. In particular, when theindicator material is placed perpendicular to the ground surface orsuspended, the oily substance is liable to run downward. However, whenthe non-woven fabric contains the above fine-denier fiber, the oilysubstance can be supported more uniformly and firmly, and the oilysubstance with which the non-woven fabric is impregnated can be moreuniformly dissipated. When the oily substance is uniformly dissipated,the process of the resin layer shifting from a visible state to a maskedstate uniformly takes place in the indicator material as an end productshifting, and a color change in the indicator material is clear. As aresult, the amount of the oily substance remaining with the passage oftime can be more clearly indicated. The indicator material I thereforeuses the "non-woven fabric containing a fine-denier fiber having a sizeof 2 denier or less" as a support.

The content of the above "fine-denier fiber having a size of 2 denier orless" in the non-woven fabric is preferably 9 to 100% by weight,particularly preferably 20 to 100% by weight. Further, the size of theabove fine-denier fiber is preferably 1 denier or less.

For obtaining a non-woven fabric which can support the oily substancevolatile at room temperature or increased temperature, to be describedlater, as uniformly as possible, the fine-denier fiber is preferably asynthetic fiber of which the form is constant and stand-like, and it isparticularly preferably a synthetic fiber of acryl, polyester,polypropylene, vinylone or nylon. The above fine-denier fiber may be anon-transparent fiber such as a fiber containing a white pigment (SD:semi-dull, D: dull) so long as there can be finally obtained a non-wovenfabric which is basically non-transparent but becomes substantiallytransparent when impregnated with the oily substance, while thefine-denier fiber is preferably a substantially transparent fibercontaining no or almost no white pigment such as titanium dioxide (SB:super bright, B: bright). A substantially transparent fiber and anon-transparent fiber may be used in combination.

The non-woven fabric containing the above fine-denier fiber may be anon-woven fabric produced by any method, while a non-woven fabricproduced by a wet paper making method is more preferred than thatproduced by a dry method in which a non-woven fabric having a relativelylow density can be produced, since a greatly uniform non-woven fabriccan be produced and since the density of the non-woven fabric can beeasily adjusted. The above term "wet paper making method" refers to amethod in which a fiber is dispersed in water to form a solution havinga low concentration of the fiber, additives such as dispersing agent, athickener and a flocculating agent are added as required, and then anon-woven fabric is produced with a cylinder paper machine, aFourdrinier paper machine, an inclined paper machine or a combinationpaper machine made of at least two paper machines. When the non-wovenfabric is produced by the wet paper making method, a non-woven fabricexcellent in fiber distribution, i.e., formation. When such a non-wovenfabric is impregnated with the oily substance to be described later, thedistribution of the oily substance is uniform, and the degree ofdissipation of the oily substance is therefore made more uniform. As aresult, in the indicator material as an end product, the process of theresin shifting from a visible state to a masked state takes place moreuniformly, and the alteration for the indicator material becomes moreclear.

When the non-woven fabric is produced, the above described fine-denierfiber alone may be used. Otherwise, a fiber other than the fine-denierfiber, such as a fiber having a binder function, a synthetic fiberhaving a size of greater than 2 denier or a natural fiber such as woodpulp, cotton or hemp may be used in combination. In particular, a fiberhaving a binder function is preferred for imparting the non-woven fabricwith strength. As a binder fiber, preferred are a heat-fusable fiber ofwhich filaments are partially or wholly softened or melted to be fusedto adjacent filaments, and a vinylon-containing binder fiber of whichfilaments are partially or wholly melted with hot water and are mutuallybonded when it is dried. On the other hand, when a natural fiber is usedin combination, it is difficult to completely wet the natural fiber withthe oily substance to be described later, or portions not wetted withthe oily substance become non-transparent in white, and the amountthereof for use is therefore properly selected for obtaining a non-wovenfabric which substantially becomes transparent when impregnated with theoily substance to be described later.

The non-woven fabric used for constituting the indicator material I maycontain a substance having a low refractive index to light, such as aninorganic pigment typified by porous silica, for permitting theobservation of a more clear process of the resin layer shifting from avisible state to a masked state in the indicator material as an endproduct. The produced non-woven fabric may be subjected to a posttreatment such as heat treatment, impregnation with a resin or calendertreatment for imparting it with desired properties. When the non-wovenfabric is produced by a wet paper making method, the produced non-wovenfabric may be subjected to a post treatment by a carding method, aneedle punching method or a spun lacing method for the purpose offurther increasing the strength of the non-woven fabric by the mutualentanglement of filaments constituting the non-woven fabric.

Although differing depending upon the amount of the oily substance to beused for the impregnation, the basis weight of the above non-wovenfabric is generally preferably 20 to 200 g/m². Further, the density ofthe non-woven fabric is preferably 0.1 to 0.5 g/cm³. When the density islower than 0.1 g/cm³, undesirably, the non-woven fabric is poor in thecapacity to support the oily substance and liquid may sag. When thedensity is higher than 0.5 g/cm³, there is no difference in the capacityto support the oily substance, but the amount of the oily substancesupported per unit area decreases and an indicator material (non-wovenfabric) having a very large area is therefore required to obtain apractical indicator material I. Since the amount of the oily substancesupported in the non-woven fabric per unit area is generally smallerthan the non-woven fabric space volume of the non-woven fabric, thenon-woven fabric space volume of the non-woven fabric used forconstituting the indicator material I is preferably at least 50 cm³ /m²,particularly preferably 50 to 1,800 cm³ /m², in practical use. The term"non-woven fabric space volume" used in the present invention refers toa value determined on the basis of the following equation.

    NS=G(1 /D-1/FD)

NS: Non-woven fabric space volume (cm³ /m²)

G: Basis weight of non-woven fabric (g/m²)

D: Density of non-woven fabric (g/cm³)

FD: Density of fiber (g/cm³)

In the indicator material I, a resin layer having a partly or whollycolored surface is formed on one surface of the above non-woven fabric.The resin layer is required to have resistance against the oilysubstance used for impregnating the above non-woven fabric, and a resinsoluble in the oily substance used for impregnating the above non-wovenfabric is not preferred. The resin layer is preferably a layer formed ofa thermoplastic resin in view of easiness in processing and easiness incoloring or printing. Polyolefin resins are particularly preferred as araw material for the resin layer, since they have resistance to almostall oily substances and have suitability for melt lamination and thecapability of forming a uniform film. Among the polyolefin resins, morepreferred are a polyethylene resin and a polypropylene resin.

Specific examples of the method of forming the above resin layer havinga partly or wholly colored surface includes the following methods (1)and (2).

(1) A method in which one surface of the non-woven fabric is providedwith a coating resin layer to coat said one surface, and the surface ofthe resin layer is colored by a printing method using a coloring ink, orthe like.

The formation of the above coating resin layer by the above method canbe carried out by an application method, a method using an adhesive, ora melt extrusion application method.

In the above application method, for example, the above coating resinlayer can be formed by dissolving a resin in a solvent to prepare acoating solution, applying the coating solution to one surface of thenon-woven fabric and drying the resultant coating. In the method usingan adhesive, for example, the above coating resin layer can be formed bybonding a resin film to one surface of the non-woven fabric by a drylaminating method or a wet laminating method. In the melt extrusionapplication method, for example, the above coating resin layer can beformed by melt-extrusion-applying a thermoplastic resin to one surfaceof the non-woven fabric.

(2) A method in which a coating resin layer having an entirely coloredsurface is directly formed on one surface of the non-woven fabric.

In the above method, the above coating resin layer having an entirelycolored surface can be formed by a method using an adhesive or a meltextrusion application method.

In the method using an adhesive, for example, the coating resin layerhaving an entirely colored surface can be formed by bonding a resin filmhaving an entirely colored surface to one surface of the non-wovenfabric by a dry laminating method or a wet laminating method. Further,in the melt extrusion application method, for example, the above coatingresin layer having an entirely colored surface can be formed bymelt-mixing a colorless thermoplastic resin and a master batch preparedby dispersing a high concentration of a coloring pigment such asultramarine, cobalt blue or the like in an extrusion application machineand melt-extrusion-applying the mixture to one surface of the non-wovenfabric.

In both the above-described methods (1) and (2), a melt-applicationmethod is preferred since a resin layer which is uniform and free of pinholes can be obtained.

The indicator material I of the present invention is obtained by formingthe above resin layer on one surface of the above non-woven fabric andimpregnating the non-woven fabric with an oily substance volatile atroom temperature or increased temperature. The term "oily substancevolatile at room temperature" in the present invention refers to an oilysubstance which volatilizes at an ambient temperature at which theindicator material is used, without heating the indicator material as anend product or without heating the ambiance in a site where theindicator material is used. The term "oily substance volatile at anincreased temperature" refers to an oily substance which does notvolatilize without heating the indicator material as an end product byproper heating means in an ambiance in a site where the indicatormaterial is used. The oily substance volatile at room temperature andthe oily substance volatile at an increased temperature having commonmeanings in the indicator material I of the present invention and theindicator material II to be described later.

Depending upon the use of the indicator material I as an end product,the above oily substance volatile at room temperature or increasedtemperature is selected, for example, from oily aromatic agents, oilydeodorants, oily mothproofing agents, oily insecticides, and the like,which are volatile at room temperature or increased temperature.

Specific examples of the oily aromatic agents and the oily deodorantsvolatile at room temperature or increased temperature include thosecontaining a component such as benzaldehyde, α-pinene, geraniol,citronellal, linalool, limonene, linaly! mentholacetate, amylcinnamicaldehyde, methyl anthranilate, isoeugenol, allyl caproate, isobutylacetate, benzyl acetate, isoamyl salicylate, citral, decyl aldehyde,hydroxycitronellal, isoamyl acetate, or the like, and plant essentialoils having aromatic deodorization effects such as bitter almond, hinokioil, nutmeg oil, geranium oil, lavender oil, lime oil, peppermint oil,vetiver oil, sweet orange oil and thyme oil.

As specific examples of the oily mothproofing agents or the oilyinsecticides volatile at room temperature or increased temperaturemothproofing agents include those containing a component such asα-pinene, eugenol, thujone, thymol, hinokitiol, cinnamic aldehyde,carvacrol, or the like, volatile pyrethroid insecticides such asempenthrin, allethrin, terallethrin, prallethrin and transfluthrin, andplant essential oils having mothproofing effects such as nutmeg oil,clove oil, sage oil, thyme oil, lavender oil, basil oil, hinoki oil,lemongrass oil, cassia oil, pimento oil and alpiniaspeclosa oil.

The method of impregnating the non-woven fabric with the oily substancevolatile at room temperature or increased temperature is not speciallylimited, while there is generally employed a method in which thenon-woven fabric is immersed in the oily substance and then compressedwith a press to adjust its content to a predetermined impregnationamount or a method in which the oily substance is directly dropwiseapplied to the non-woven fabric with a syringe and its content isadjusted to a predetermined impregnation amount. It is sufficient to usethe oily substance in such an impregnation amount that the non-wovenfabric becomes substantially transparent when impregnated with the oilysubstance. The above amount can be properly set in an amount range whichgenerally does not exceed the non-woven fabric space volume, dependingupon the non-woven fabric space volume and the use of the indicatormaterial I as an end product.

The indicator material I of the present invention can be obtained byimpregnating the non-woven fabric, of which one surface is provided withthe predetermined resin layer, with the oily substance volatile at roomtemperature or increased temperature as described above. The indicatormaterial I may be used as it is. For preventing the contact of the oilysubstance volatile at room temperature or increased temperature toarticles around it, however, it is generally preferred to place it in acontainer of plastic, paper or a metal before setting it in a desiredplace. In this case, it is preferred to provide part of the containerwith an aperture, etc., such that a change in the indicator material Ican be observed from outside of the container, i.e., such that the resinlayer which is observable from the non-woven fabric side can be observedfor a color change.

For example, when the volatile oily substance is a mothproofing agentvolatile at room temperature, the above indicator material I can be usedby directly placing it in a drawer of a chest. When the volatile oilysubstance is a deodorant volatile at room temperature, the indicatormaterial I can be used by directly placing it in a room, in a rest room,a hall, an automobile, a refrigerator, or the like. When the volatileoily substance is an aromatic agent volatile at room temperature, theindicator material I can be used by directly placing it in a room, arest room, a hall, an automobile, or the like. When the volatile oilysubstance is an insecticide volatile at an increased temperature, theindicator material I can be used by combining it with heating means usedin an electrical mosquito preventing device and placing the combinationin a room.

In the indicator material I used as described above, the non-wovenfabric impregnated with a sufficient amount of the oily substance issubstantially transparent, and a color of the colored portion of theresin layer formed on one surface of the non-woven fabric can be clearlyobserved when it is observed from the non-woven fabric side. However,the dissipation of the oily substance in the non-woven fabric occurs inthe side opposite to the resin layer side, and the non-woven fabricgradually becomes non-transparent because of the dissipation of the oilysubstance which occurs with the passage of time. And, the non-wovenfabric finally comes into a non-transparent state. Therefore, the resinlayer observed from the non-woven fabric side gradually shifts from avisible state to a state masked by the non-woven fabric due to thedissipation of the oily substance which occurs with the passage of time.With the above shifting, a color observable from the non-woven fabricside gradually alters from the color of colored portion of the resinlayer to the color of the non-woven fabric itself. That is, theindicator material I gradually and continuously changes in color fromthe color of the colored portion of the resin layer to the color of thenon-woven fabric itself in accordance with a change in the degree ofdissipation of the oily substance volatile at room temperature orincreased temperature with which the non-woven fabric is impregnated.Therefore, the degree of dissipation of the oily substance volatile atroom temperature or increased temperature can be recognized at a glanceby observing the above change in color.

Further, as shown in FIG. 6, when a print portion 23 of a character, aprint, or the like showing the termination of dissipation(disappearance) of the oily substance (not shown) volatile at roomtemperature or increased temperature with which the non-woven fabric 21is impregnated, in a similar color having a lower intensity than thecolored portion of the resin layer 22, is provided, by a printingmethod, on a surface 21b opposite to a surface 21a of the non-wovenfabric 21 on which the resin layer 22 is formed, the dissipation(disappearance) of the oily substance with which the non-woven fabric 21is impregnated can be more effectively shown. The term "similar colorhaving a lower intensity than the colored portion of the resin layer"refers to a color which is similar to, or has the same color tone as,that of the colored portion of the resin layer, but has a lowerintensity than the same. In FIG. 6, members which appear in FIG. 5 areshown by the same reference numerals as those in FIG. 5.

The above print portion 23 may be of a character, a symbol, a paintingor anything else. For example, the character may read "please replace","termination of dissipation", "end", "END", etc., and the symbol may be"X", etc. The method of providing the above print portion 23 is notspecially limited, and it is selected from a screen printing method, agravure printing method, an offset printing method, a relief printingmethod and an inkjet printing method.

The print portion 23 is prepared so as to show a similar color having alower intensity than the colored portion of the resin layer 22, and whenthe non-woven fabric 21 is transparent due to the impregnation with theoily substance, the print portion 23 is therefore similar to the colorof colored portion of the resin layer 21 and is not decipherable even ifthe observation is made toward the resin layer 22 from the non-wovenfabric 21 side. With the dissipation (disappearance) of the oilysubstance, the non-woven fabric 21 gradually becomes non-transparent,and the color of colored portion of the resin layer 22 decreases inintensity when observed. The print portion 23 provided on the non-wovenfabric 21 accordingly gradually becomes decipherable, whereby thedissipation (disappearance) of the oily substance volatile at roomtemperature or increased temperature with which the non-woven fabric 21is impregnated can be more effectively shown.

In the indicator material I, for effectively showing the degree of theoily substance volatile at room temperature or increased temperaturewith which the non-woven fabric is impregnated, preferably, the color ofthe non-woven fabric (color recognized when the non-woven fabric itselfis observed, the term will be used in this sense hereinafter) isarranged to be white or similar to white, and the color of coloredportion of the resin layer is arranged to be a deep color such as black,blue, red, green, violet, etc., as far as it is permitted. When thecolor of the non-woven fabric and the color of colored portion of theresin layer are selected as above, these colors have a high contrast,and the color change dependent upon the degree of dissipation of theoily substance volatile at room temperature or increased temperaturebecomes clearer.

The above-explained indicator material I works not only as a dissipationdevice which dissipates the oily substance volatile at room temperatureor increased temperature with which the non-woven fabric is impregnated,but also as one having the indicator function to show the dissipationamount of the above oily substance. And, the non-woven fabric as asupport works as a container for the oily substance volatile at roomtemperature or increased temperature.

Containing a fine-denier fiber having a size of 2 denier or less, theabove non-woven fabric can support the oily substance more firmly anduniformly than a non-woven fabric which does not contain the fine-denierfiber. As a result, the oily substance with which the non-woven fabricis impregnated can be more uniformly dissipated. In the indicatormaterial I, further, the resin layer gradually becomes masked by thenon-woven fabric with the dissipation of the oily substance, and theabove non-woven fabric is highly capable of masking the resin layer. Inthe indicator material I of the present invention, therefore, the sitewhere to set it and the method of setting it are negligible, andfurther, the degree of dissipation of the oily substance which occurswith the passage of time can be clearly shown.

Further, containing a fine-denier fiber having a size of 2 denier orless, the above non-woven fabric is relatively highly capable ofsupporting the oily substance over a non-woven fabric which does notcontain the fine-denier fiber, and the indicator material I of thepresent invention can therefore contain a relatively large amount of theoily substance.

The indicator material II of the present invention will be explainedhereinafter.

The indicator material II of the present invention is the same as theabove indicator material I except that the non-woven fabric which has alow refractive index and is used as a support has a partly altereddensity and that the non-woven fabric is not required to contain afine-denier fiber having a size of 2 denier or less. Nevertheless, it ispreferred to use a non-woven fabric containing a fine-denier fiberhaving a size of 2 denier or less for allowing the non-woven fabric tosupport the oily substance firmly and uniformly. Specific examples ofthe above non-woven fabric include those described in the explanation ofthe indicator material I.

The density of the non-woven fabric constituting the indicator materialII partly altered, and the non-woven fabric therefore has a portionhaving a relatively high density and a portion having a relatively lowdensity. In the non-woven fabric, the density of the "portion having ahigh density" (to be referred to as "high-density portion" hereinafter)is preferably 0.3 to 1.0 g/cm³, and the density of the "portion having alow density" (to be referred to as "low-density portion" hereinafter) ispreferably 0.1 to 0.5 g/cm³. When the above density is lower than the0.1 g/cm³, undesirably, the non-woven fabric is poor in the capacity tosupport the volatile oily substance, and the oily substance may sag.When the above density is higher than 1.0 g/cm³, there is no problem onthe capacity to support the oily substance, while the showing functionexhibited by the resin layer shifting from a visible state to a statemasked by the non-woven fabric is no longer clear. The amount of theoily substance supported per unit area of the non-woven fabric isgenerally equivalent to, or smaller than, the non-woven fabric spacevolume of the non-woven fabric, and the space volume of the non-wovenfabric used in the indicator material II is therefore preferably atleast 50 cm³ /m³, particularly preferably 50 to 1,800 cm³ /m³ when thenon-woven fabric is considered as a whole. The above range of thehigh-density portion and the above range of the low-density portionpartly overlap, while the density of the former is naturally not higherthan the density of the latter.

The high-density portion and the low-density portion can be disposed asrequired depending upon the use of the indicator material II as an endproduct. For example, the half of area of the non-woven fabric takenalong the longitudinal direction or the transverse direction is arrangedto be a high-density portion, and the remaining half is arranged to be alow-density portion. Further, the high-density portion and thelow-density portion may be arranged such that they form the pattern of alattice, a check, a honeycomb, a hexagon or concentric circles when thenon-woven fabric is seen from the above. When the high-density portionand the low-density portion are disposed such that the high-densityportion is surrounded by the low-density portion, the degree ofdissipation of the oily substance can be more clearly shown. The reasontherefore is assumed to be as follows.

The oily substance with which the non-woven fabric is impregnateddissipates from both the low-density portion and the high-densityportion, while the oily substance present in the low-density portionspontaneously shifts into the high-density portion with the dissipationof the oily substance from the high-density portion. When thehigh-density portion is disposed such that part of the high-densityportion is located in an edge portion of the non-woven fabric, theinitial shifting of the oily substance from the low-density portion tothe high-density portion with the dissipation of the oily substance islimited to the shifting of the oily substance from the low-densityportion to that part of the high-density portion which is not located inthe edge portion of the non-woven fabric. On the other hand, when thehigh-density portion and the low-density portion are disposed such thatthe high-density portion is surrounded by the low-density portion, theinitial shifting of the oily substance from the low-density portion tothe high-density portion with the dissipation of the oily substancetakes place in all directions toward the high-density portion whenviewed from the above. The shifting of the oily substance thereforetakes place more effectively. Therefore, the oily substance remains inthe high-density portion surrounded by the low-density portion evenafter the oily substance in the surrounding low-density portion hasdisappeared, and the degrees of color change with the dissipation of theoily substance therefore differ to a great extent between thehigh-density portion and the low-density portion when the indicatormaterial II is observed from the non-woven fabric side. As a result, thedegree of the oily substance can be more clearly shown.

The degree of process of the above color change in the high-densityportion also depends upon to what extent the oily substance shifts fromthe low-density portion to the high-density portion. The degree ofprocess of the above color change in the high-density portion thereforediffers depending upon how the high-density portion is in contact to thelow-density portion. Therefore, the time length required for the resinlayer shifting from a visible state to a masked state in thehigh-density portion can be determined by adjusting how the high-densityportion is in contact with the low-density portion when the high-densityportion is formed.

The partly altered density of the non-woven fabric may be formed of twodifferent density portions, a low-density portion and a high-densityportion, may be formed of three different density portions, alow-density portion, an intermediate-density portion and a high-densityportion, or may be formed of at least four different density portions.

The above non-woven fabric having a partly altered density can beobtained by preparing a non-woven fabric having a substantially uniformdensity by a dry method, a wet paper making method, or the like, andthen partly roughening a desired portion on the surface of the non-wovenfabric or pressing a desired portion of the non-woven fabric with apress roll, a hot press roll, an embossing roll, an embossing machine orthe like. Further, the above non-woven fabric can be also obtained bycombining non-woven fabrics having different densities. In the method ofobtaining the non-woven fabric having a partly altered density bypressing a desired portion of a non-woven fabric, the processing is easysince a pressed portion alone has an increased density, and the form ofa portion of which the density is desired to alter can be determined asrequired. The above method is therefore suitable as a method of partlyaltering the density of the non-woven fabric.

The basis weight of the "non-woven fabric having a partly altereddensity" differs depending upon the amount of the oily substance usedfor impregnating the non-woven fabric, while it is generally preferably20 to 200 g/m².

In the indicator material II, a partly or wholly colored resin layer isformed on one surface of the above non-woven fabric. The material forthe resin layer and the method of the formation thereof are the same asthose explained with regard to the indicator material I, and theirexplanations are omitted here.

Like the oily substance used in the already described indicator materialI, the oily substance volatile at room temperature or increasedtemperature used for impregnating the above non-woven fabric providedwith the resin layer is selected, for example, from an oily aromatic,oily deodorants, oily mothproofing agents, oily insecticides, and thelike, which are volatile at room temperature or increased temperature,depending upon use of the indicator material II as an end product.Specific examples of the above oily substance include those specifiedwith regard to the already explained indicator material I of the presentinvention. Further, concerning the method of impregnating the non-wovenfabric with the oily substance, the method shown in the explanation ofthe indicator material I of the present invention can be appliedthereto.

The indicator material II of the present invention can be obtained byimpregnating the non-woven fabric having one surface provided with theresin layer with oily substance volatile at room temperature orincreased temperature. The indicator material II may be used as it is.As described with regard to the indicator material I, however, it ispreferred to place it in a container of plastic, paper or a metal beforesetting it in a desired place. In this case, it is preferred to providepart of the container with an aperture, etc., such that a change in theindicator material IL can be observed from outside of the container,i.e., such that the resin layer which is observable from the non-wovenfabric side can be observed for a color change. Like the indicatormaterial I, the indicator material II is used by placing it in a desiredplace depending upon the kind of the oily substance used forimpregnating the non-woven fabric.

In the indicator material II used as described above, the non-wovenfabric impregnated with a sufficient amount of the oily substance issubstantially transparent, and a color of the colored portion of theresin layer formed on one surface of the non-woven fabric can be clearlyobserved when it is observed from the non-woven fabric side. However,the dissipation of the oily substance in the non-woven fabric occurs inthe side opposite to the resin layer side, and the non-woven fabricgradually becomes non-transparent because of the dissipation of the oilysubstance which occurs with the passage of time. And, the non-wovenfabric finally comes into a non-transparent state. Therefore, the resinlayer observed from the non-woven fabric side gradually shifts from avisible state to a state masked by the non-woven fabric due to thedissipation of the oily substance which occurs with the passage of time.With the above shifting, a color observable from the non-woven fabricside gradually alters from the color of colored portion of the resinlayer to the color of the non-woven fabric itself. And, the above colorchange proceeds at a higher rate in the low-density portion than in thehigh-density portion of the non-woven fabric. The color change in thehigh-density portion and the color change in the low-density portion canbe compared for confirmation, whereby the degree of dissipation of theoily substance can be more clearly recognized.

In the indicator material II of the present invention, for more clearlyshowing the dissipation (disappearance) of the oily substance with whichthe non-woven fabric is impregnated, a print portion showing thetermination of dissipation of the oily substance may be prepared in asimilar color having a lower intensity than the colored portion of theresin layer, and provided on a surface which is opposite to the surfaceof the non-woven fabric provided with the resin layer and has a highdensity in the non-woven fabric (the above print portion will bereferred to as "print portion i" hereinafter). The print portion i maybe of a character, a symbol, a painting or anything else. For example,the character may read "please replace", "termination of dissipation","end", "END", etc., and the symbol may be "X", etc.

Further, a print portion showing that the oily substance is beingdissipated, in a color which is similar to that of the colored portionof the resin layer but has a higher or equivalent intensity or is thesame as that of the non-woven fabric, may be provided on a surface whichis opposite to the surface of the non-woven fabric provided with theresin layer and has a low density in the non-woven fabric (the aboveprint portion will be referred to as "print portion ii" hereinafter).The print portion ii may be of a character, a symbol, a painting oranything else. For example, the character may read "in use","dissipating", "working", etc., and the symbol may be "→→→", etc.

The print portion ii of a symbol such as "→→→", "↑↑↑↑" or the like, adesired character or a painting may be provided in a color which issimilar to that of the non-woven fabric such that the print portion iiis present in each of the low-density portion and the high-densityportion or that the print portion ii bridges the low-density portion andthe high-density portion.

The method of providing the above print portions i and ii maybe anymethod without any special limitation. There may be employed a screenprinting method, a gravure printing method, an offset printing method, arelief printing method, an inkjet printing method or the like.

When the above print portion i is formed on the surface of thehigh-density portion of the non-woven fabric, the print portion i issimilar to the color of colored portion of the resin layer and is notvisually recognizable, since the non-woven fabric is substantiallytransparent at a time when the non-woven fabric is impregnated with theoily substance. With the dissipation (disappearance) of the oilysubstance, the non-woven fabric becomes gradually non-transparent sothat the intensity of the color of the colored portion of the resinlayer decreases, and the print portion i becomes decipherable. As aresult, the degree of dissipation of the oily substance can be morefinely shown.

When the above print portion i is formed on the surface of thehigh-density portion of the non-woven fabric and when the above printportion ii is provided in a color which has an intensity higher than, orequivalent to, the color of colored portion of the resin layer and isthe same color as that of the colored portion, stepwise showing stateslike the following first to final steps can be achieved.

That is, in a first step, the non-woven fabric is substantiallytransparent, and the whole surface of the indicator material thereforeshows the color of colored portion of the resin layer when theobservation is made toward the resin layer side from the non-wovenfabric side, so that it is confirmed that the non-woven fabric isimpregnated with the oily substance.

A second step is there for a certain period of time after the initiationof use. In the second step, the color change with the dissipation of theoily substance proceeds at a higher rate in the low-density portion thanin the high-density portion, and the print portion ii begins to appear.However, when the color of the print portion ii is the same color asthat of the colored portion of the resin layer and has an intensityequivalent to that of the colored portion, the print portion ii is notyet visually recognizable. On the other hand, in a portion where thecolor change proceeds at a lower rate (high-density portion of thenon-woven fabric), no change is visually recognizable, and this portionshows the color of colored portion of the resin layer.

In a subsequent third step, the color change with the dissipation of theoily substance further proceeds, and the low-density portion of thenon-woven fabric becomes visually recognizable in a color of which theintensity is lower than that of the colored portion of the resin layer.As a result, the print portion ii comes into a state where the printportion ii is decipherable even if the print portion ii has the samecolor as that of the colored portion of the resin layer and has anintensity equivalent to that of the colored portion. In a portion wherethe color change proceeds at a lower rate (high-density portion of thenon-woven fabric), however, the change is not yet visually recognizable.

In a subsequent fourth step, the color change with dissipation of theoily substance further proceeds, and the low-density portion of thenon-woven fabric comes to show the original color of the non-wovenfabric itself. In this portion, the resin layer is masked by thenon-woven fabric, and the print portion ii is therefore clearly shown.On the other hand, in the portion where the color change proceeds at alower rate (high-density portion of the non-woven fabric), the colorchanges to a low-intensity color. Since, however, the print portion i isalso formed of a low-intensity color, the print portion i showing theend of dissipation is not yet visually recognizable.

In a final step, all of the oily substance used for the impregnation ofthe non-woven fabric are dissipated, both the portion where the colorchange proceeds at a higher rate (low-density portion of the non-wovenfabric) and the portion where the color change proceeds at a lower rate(high-density portion of the non-woven fabric) show the color of thenon-woven fabric itself, and the resin layer is masked by the non-wovenfabric. Therefore, not only the print portion ii but also the printportion i are clearly shown. That is, the end of dissipation of the oilysubstance is clearly shown.

Further, when the print portion i is formed on the surface of thehigh-density portion of the non-woven fabric and when the print portionii in the same color as that of the non-woven fabric is formed on thesurface of the low-density portion of the non-woven fabric, stepwiseshowing states like the following first to final steps can be achieved.

That is, in a first step, the non-woven fabric is substantiallytransparent, and the print portion ii is formed in the same color asthat of the non-woven fabric itself. Therefore, when the observation ismade toward the resin layer from the non-woven fabric side, the printportion ii is clearly visually recognized, and the other portion showsthe color of colored portion of the resin layer. The portion other thanthe print portion ii shows the color of colored portion of the resinlayer, and it can be therefore confirmed that the non-woven fabric isimpregnated with the oily substance.

A second step is there for a certain period of time after the initiationof use. In the second step, the color change with the dissipation of theoily substance proceeds at a higher rate in the low-density portion ofthe non-woven fabric than in the high-density portion, while the printportion ii is still visually recognizable since the print portion ii isformed in the same color as that of the non-woven fabric itself. On theother hand, in the portion where the color change proceeds at a lowerrate (high-density portion of the non-woven fabric), no change isrecognizable, and this portion shows the color of colored portion of theresin layer.

In a subsequent third step, the color change with the dissipation of theoily substance further proceeds, and the color on the portion where thecolor change proceeds at a higher rate (low-density portion of thenon-woven fabric) changes to a low-intensity color. It is thereforebecomes difficult to recognize the print portion ii, while the printportion ii is still visually recognizable. On the other hand, in theportion where the color change proceeds at a lower rate (high-densityportion of the non-woven fabric), the change is not yet recognizable.

In a subsequent fourth step, the color change with the dissipation ofthe oily substance further proceeds, and the low-density portion of thenon-woven fabric comes to show the original color of the non-wovenfabric itself. Therefore, the print portion ii formed in the same coloras that of the non-woven fabric itself becomes visually unrecognizable.On the other hand, the portion where the color change proceeds at alower rate (high-density portion of the non-woven fabric) is altered toa low-intensity color. Since, however, the print portion i is formed ina similar color having a lower intensity than the colored portion of theresin layer, the print portion i is not visually recognizable in thisstate.

In a final step, all of the oily substance used for the impregnation ofthe non-woven fabric is dissipated, and both of the portion where thecolor change proceeds at a higher rate (low-density portion of thenon-woven fabric) and the portion where the color change proceeds at alower rate (high-density portion) come to show the color of thenon-woven fabric itself. Therefore, the print portion ii formed in thecolor similar to the color of the non-woven fabric itself is notvisually recognizable as is not in the fourth step, while the printportion i formed in the similar color having a lower intensity than thecolored portion of the resin layer is clearly shown. That is, the end ofdissipation of the oily substance is clearly shown.

Further, when the print portion ii of a symbol such as "→→→", "↑↑↑↑" orthe like, a desired character or a painting may be provided in a colorwhich is similar to that of the non-woven fabric such that the printportion ii is present in each of the low-density portion and thehigh-density portion or that the print portion ii bridges thelow-density portion and the high-density portion, stepwise showingstates like the following first to final steps can be achieved.

That is, in a first step, the non-woven fabric is substantiallytransparent, and the print portion ii is formed in the same color asthat of the non-woven fabric. When the observation is made toward theresin layer side from the non-woven fabric side, the print portion ii asa whole is clearly visually recognized, and the other portion shows thecolor of colored portion of the resin layer. Since the portion otherthan the print portion ii shows the color of colored portion of theresin layer, it is confirmed that the non-woven fabric is impregnatedwith the oily substance.

A second step is there for a certain period of time after the initiationof use. In the second step, the color change with the dissipation of theoily substance proceeds at a higher rate in the low-density portion ofthe non-woven fabric than in the high-density portion, while the printportion ii as a whole is still visually recognizable since the printportion ii is formed in the same color as that of the non-woven fabricitself.

In a subsequent third step, the color change with the dissipation of theoily substance further proceeds, and the color of the portion where thecolor change proceeds at a higher rate (low-density portion of thenon-woven fabric) therefore alters to a low-intensity color, so that itbecomes difficult to visually recognize the print portion ii on thatportion. However, the print portion ii on that portion is stillrecognizable. On the other hand, the print portion ii on the portionwhere the color change proceeds at a lower rate (high-density portion ofthe non-woven fabric) is still clearly visually recognizable.

In a subsequent fourth step, the color change with the dissipation ofthe oily substance further proceeds, and the low-density portion of thenon-woven fabric comes to show the original color of the non-wovenfabric itself. Therefore, that portion of the print portion ii which isformed on the portion where the color change proceeds at a higher rate(low-density portion of the non-woven fabric) becomes visuallyunrecognizable. On the other hand, the portion where the color changeproceeds at a lower rate (high-density portion of the non-woven fabric)alters to a low-intensity color, while the print portion ii on the aboveportion is still visually recognizable since the print portion ii isformed in the same color as that of the non-woven fabric.

In a final step, all of the oily substance used for the impregnation ofthe non-woven fabric is dissipated, and both of the portion where thecolor change proceeds at a higher rate (low-density portion of thenon-woven fabric) and the portion where the color change proceeds at alower rate (high-density portion) come to show the color of thenon-woven fabric itself. Therefore, the print portion ii formed in thecolor similar to the color of the non-woven fabric itself is notvisually recognizable. That is, the end of dissipation of the oilysubstance is clearly shown.

In the indicator material II as well as the indicator material I, foreffectively showing the degree of the oily substance volatile at roomtemperature or increased temperature with which the non-woven fabric isimpregnated, preferably, the color of the non-woven fabric (color of thenon-woven fabric before it is impregnated with the oily substance) isarranged to be white or similar to white, and the color of the resinlayer is arranged to be a deep color such as black, red, green, violet,etc., as far as it is permitted. When the color of the non-woven fabricand the color of colored portion of the resin layer are selected asabove, these colors have a high contrast, and the color change dependentupon the degree of dissipation of the oily substance volatile at roomtemperature or increased temperature becomes clearer.

The above-explained indicator material II works not only as adissipation device which dissipates the oily substance volatile at roomtemperature or increased temperature with which the non-woven fabric isimpregnated, but also as one having the indicator function to show thedissipation amount of the above oily substance. And, the non-wovenfabric as a support works as a container for the oily substance volatileat room temperature or increased temperature.

Having partly altered density, the above non-woven fabric has a portionwhere the color change with the dissipation of the oily substance whichoccurs with the passage of time proceeds at a higher rate (low-densityportion) and a portion where the above color change proceeds at a lowerrate (high-density portion). The indicator material II can therefore canclearly show not only a time of expiration of the oily substance butalso the degree of dissipation of the oily substance which occurs withthe passage of time, based on a difference between the color change inthe portion where the color change with the dissipation of the oilysubstance which occurs with the passage of time proceeds at a higherrate (low-density portion) and the portion where the above color changeproceeds at a lower rate (high-density portion). Further, the colorchange in the above portion where the color change proceeds at a higherrate and the color change in the above portion where the color changeproceeds at a lower rate take place independently of each othersubstantially regardless of a place where the indicator material II isset and the method of setting it. The indicator material II can betherefore set in any site and by any method so long as it is in a statewhere the observation can be made toward the resin layer side from thenon-woven fabric side.

When a non-woven fabric containing a fine-denier fiber having a size of2 denier or less is used as the above non-woven fabric, not only theoily substance used for the impregnation of the non-woven fabric can bemore uniformly dissipated, but also the capability of masking the resinlayer with the non-woven fabric is improved, similarly to the indicatormaterial I. The indicator material II can therefore more clearly shownot only a time of expiration of the oily substance but also the degreeof dissipation of the oily substance which occurs with the passage oftime. At the same time, the capacity of the non-woven fabric to supportthe oily substance relatively improves, and the indicator material IIcan therefore contain a relatively large amount of the oily substance.

The present invention will be explained more in detail with reference toExamples hereinafter, while the content of the present invention shallnot be limited to the following Examples, in which "part" stands for"part by weight".

EXAMPLES 1-13

(Preparation of indicator material I) and Comparative Examples 1-2

Fabrics were prepared from fibers shown in Table 1 or 2 in amounts shownin Table 1 or 2 by a wet paper making method using a cylinder papermachine, and then a wet press part, a dry part and a calender part wereproperly adjusted in each of Examples and Comparative Examples toprepare non-woven fabrics as a support. In Example 13 alone, however,the non-woven fabric was prepared by a dry method (carding method).These non-woven fabrics showed white as original color, and all thenon-woven fabrics had a refractive index of 1.7 or less. Table 1 or 2shows the basis weights, densities and non-woven fabric space volumes ofthe so-obtained non-woven fabrics.

A resin composition prepared by incorporating 1% of Blue Ultramarineinto a low-density polyethylene (NUC8008, supplied by Nippon Unicar) wasapplied to one surface of each of the above non-woven fabrics by meltextrusion at a resin temperature of 320° C. to form a resin layer ofwhich the entire surface was colored in deep blue. In the application bymelt extrusion, a melt extrusion application machine was used, and theapplication amount of the resin was set at 20 g/m².

The above non-woven fabrics each of which had one surface on which theresin layer was formed, were receptively impregnated with 100 g/m² ofisobutyl acetate, whereby indicator materials I included in the presentinvention were obtained in Examples 1 to 13, and indicator materials notincluded in the present invention were obtained in Comparative Examples1 and 2.

Among the above indicator materials, all the indicator materials Iincluded in the present invention could clearly show the degree ofdissipation of the oily substance (isobutyl acetate) with the passage oftime even if they were set horizontally, set slantly or suspendedvertically. These data show that these indicator materials I can be usedregardless of a setting site and a setting method. The indicatormaterials obtained in Examples 1 to 13 and Comparative Examples 1 and 2were determined or evaluated for performances by the following methods.

Visibility of resin layer!

When the indicator materials I were observed from the non-woven fabricside to the resin layer side, it was determined how clearly the color ofthe resin layer could be visually recognized.

A: The color of the resin layer could be clearly recognized.

B: The indicator material had an intermediate performance between A andC.

C: The color of the resin layer was whitish to some extent, but could berecognized.

D: The indicator material had an intermediate performance between C andE (different from E in which the indicator material could not be put touse).

E: No color of the resin layer could be recognized.

Capability of masking resin layer!

When the indicator materials I were observed from the non-woven fabricside to the resin layer side at a time when the oily substance wascompletely dissipated by allowing the indicator materials I to stand atroom temperature, the capability of masking the resin layer with thenon-woven fabric was determined.

A: The masking capability of the non-woven fabric was perfect so that nocolor of the resin layer could be recognized.

B: The indicator material had an intermediate performance between A andC.

C: The masking capability of the non-woven fabric was imperfect to someextent, and the color of the resin layer could be recognized to someextent.

D: The indicator material had an intermediate performance between C andE (different from E in which the indicator material could not be put touse).

E: The masking capability of the non-woven fabric was imperfect, and thecolor of the resin layer could be recognized.

Capability of shifting in showing!

The indicator materials I were allowed to stand at room temperature, andcolor changes with the passage of time when the indicator materials wereobserved from the non-woven fabric side to the resin layer side wereevaluated.

A: The indicator material showed a clear color change.

B: The indicator material had an intermediate performance between A andC.

C: The indicator material showed a color change although it was unclearto some extent.

D: The indicator material had an intermediate performance between C andE (different from E in which the indicator material could not be put touse).

E: The indicator material showed almost no color change.

Capacity to support oily substance!

The indicator materials I were perpendicularly suspended, and a degreeto which the oily substance was held in the indicator material wasdetermined.

A: No oily substance leaked from the indicator material.

B: The indicator material had an intermediate performance between A andC.

C: A puddle of the oily substance was formed below the indicatormaterial.

D: The indicator material had an intermediate performance between C andE (different from E in which the indicator material could not be put touse).

E: The oily substance leaked from the indicator material.

                  TABLE 1    ______________________________________                         Basis           Space    Fibers and their amounts for                         weight  Density volume    non-woven fabric     g/m.sup.2                                 g/cm.sup.3                                         cm.sup.3 /m.sup.2    ______________________________________    Example           Acrylic fiber (supplied by                             50      0.25  151.9    1      Mitsubishi Rayon Co., Ltd.)           0.1 d *1, 3 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           2d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             50      0.22  179.2    2      Mitsubishi Rayon Co., Ltd.)           0.5 d, 3 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           2d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             50      0.21  190.0    3      Mitsubishi Rayon Co., Ltd.)           1.5 d, 3 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           2d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             50      0.20  201.9    4      Mitsubishi Rayon Co., Ltd.)           2 d, 3 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           2d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             45      0.20  181.7    5      Mitsubishi Rayon Co., Ltd.)           1.0 d, 3 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 50 parts    Example           Polyester fiber -B*2 (supplied                             45      0.20  186.0    6      by Kuraray Co., Ltd.)           1.3 d, 5 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           2d, 5 mm, 50 parts    Example           Polyester fiber-SD*3 (supplied                             45      0.20  186.0    7      by Teijin Ltd.)           1.5 d, 5 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           2d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             50      0.28  135.0    8      Mitsubishi Rayon Co., Ltd.)           0.5 d, 3 mm, 40 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 30 parts           Natural pulp (LBKP)           30 parts    ______________________________________     *1: d stands for denier.     *2: B stands for "bright" and means that a fiber contains no, or very     small amount of, white pigment. The color of the fiber is transparent.     *3: SD stands for semidouble and means that a fiber contains a white     pigment. The color of the fiber is white.

                  TABLE 2    ______________________________________                         Basis           Space    Fibers and their amounts for                         weight  Density volume    non-woven fabric     g/m.sup.2                                 g/cm.sup.3                                         cm.sup.3 /m.sup.2    ______________________________________    Example           Acrylic fiber (supplied by                             40      0.15  228.2    9      Mitsubishi Rayon Co., Ltd.)           1.0 d, 3 mm, 9 parts           Acrylic fiber (supplied by           Mitsubishi Rayon Co., Ltd.)           3.0 d, 3 mm, 41 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             40      0.18  183.8    10     Mitsubishi Rayon Co., Ltd.)           1.0 d, 3 mm, 20 parts           Acrylic fiber (supplied by           Mitsubishi Rayon Co., Ltd.)           3.0 d, 3 mm, 30 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             40      0.14  247.3    11     Mitsubishi Rayon Co., Ltd.)           1.0 d, 3 mm 5 parts           Acrylic fiber (supplied by           Mitsubishi Rayon Co., Ltd.)           3.0 d, 3 mm, 45 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 50 parts    Example           Acrylic fiber (supplied by                             30      0.09  304.5    12     Mitsubishi Rayon Co., Ltd.)           1.0 d, 3 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 50 parts    Example           Polyester fiber -B (supplied by                             40      0.10  365.4    13     Kuraray Co., Ltd.)           2 d, 51 mm, 50 parts           Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           2d, 51 mm, 50 parts           Produced by dry method           (carding method)    Compara-           Acrylic fiber (supplied by                             40      0.15  228.2    tive   Mitsubishi Rayon Co., Ltd.)    Example           3.0 d, 3 mm, 80 parts    1      Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 20 parts    Compara-           Polyester fiber -B (supplied by                             40      0.15  232.2    tive   Kuraray Co., Ltd.)    Example           3.0 d, 5 mm, 70 parts    2      Heat-fusible fiber (NBF-E,           supplied by Daiwabo)           3d, 5 mm, 30 parts    ______________________________________

Comparative Example 3

A non-woven fabric as a support was prepared from 50 parts of an acrylicfiber (supplied by Mitsubishi Rayon Co., Ltd., 0.1 d, 3 mm) and 50 partsof a heat-fusible fiber (NBF-E, supplied by Daiwabo, 2 d, 5 mm) by a wetpaper making method using a cylinder paper machine. The preparednon-woven fabric had a basis weight of 50 g/m and a density of 0.33g/cm³. No resin layer was formed.

Comparative Example 4

A resin composition prepared by incorporating 1% of Blue Ultramarineinto a low-density polyethylene (NUC8008, supplied by Nippon Unicar) wasapplied by melt extrusion at a resin temperature of 320° C. to obtain a50 g/m² film, which was used as a resin layer. No support of a non-wovenfabric was formed.

The indicator materials of Examples 1 to 13 and Comparative Examples 1and 2 shown in Table 1 or 2 and the indicator materials of ComparativeExamples 3 and 4 were determined or evaluated for visibility of resin,capability of masking resin, capability of shifting in showing andcapacity to support oily substance, and Table 3 shows the results. Thosefound in the determination or evaluation of the above characteristicsare shown in the column of Remarks.

                  TABLE 3    ______________________________________               Capa-    Capa-    Visi-      bility of                        bility of                                Capacity    bility of  masking  shifting                                to hold    resin      resin    in      oily    layer      layer    showing substance                                       Remarks    ______________________________________    Ex. 1  A       A        A     A      --    Ex. 2  A       A        A     A      --    Ex. 3  A       B        A     B      --    Ex. 4  A       C        A     C      --    Ex. 5  A       B        A     B      --    Ex. 6  A       B        A     B      --    Ex. 7  C       B        C     B      --    Ex. 8  C       A        C     A      --    Ex. 9  A       C        C     C      --    Ex. 10 A       B        B     B      --    Ex. 11 A       D        D     D      --    Ex. 12 A       C        C     D      --    Ex. 13 A       C        D     D      As compared with                                         non-woven fabric                                         prepared by wet                                         method, the                                         formation was                                         poor, and the                                         evaluation                                         varied.    CEx. 1 A       D        D     E      --    CEx. 2 A       D        D     E      --    CEx. 3 E       E        E     A      Since no resin                                         layer was                                         formed, there                                         was no color                                         change.    CEx. 4 E       E        E     E      Could not be                                         impregnated with                                         isobutyl                                         acetate.    ______________________________________     Ex. = Example, CEx. = Comparative Example

EXAMPLE 14

(Preparation of indicator material I)

A non-woven fabric as a support was prepared in the same manner as inExample 1, and a resin layer was formed on one surface of the abovenon-woven fabric in the same manner as in Example 1 except that BlueUltramarine was not incorporated into a low-density polyethylene(NUC8008, supplied by Nippon Unicar Co., Ltd.) or that the low-densitypolyethylene alone was used as a raw material for the resin layer. Then,printing was conducted on the surface of the above resin layer in indigoblue by an offset printing method using an indigo blue ink (TSP202 Blue,supplied by Toyo Ink Manufacturing Co., Ltd.).

Then, the above non-woven fabric was impregnated with isobutyl acetatein the same manner as in Example 1 to give an indicator material I.

The obtained indicator material I was determined or evaluated forperformances in the same manner as in Example 1 to show that it could beset regardless of a setting site and a setting method and that it couldclearly show the degree of dissipation of the oily substance (isobutylacetate) with the passage of time.

EXAMPLE 15

(Preparation of indicator material I)

A non-woven fabric provided with a resin layer on one surface wasprepared in the same manner as in Example 1 , and then a print portionof "End" was formed on a surface opposite to the resin layer, i.e., onthe non-woven fabric surface by an offset printing method using atinting shade blue ink (TSP202 Blue, supplied by Toyo Ink ManufacturingCo., Ltd.) which was a similar color having a lower intensity than thecolor of the resin layer.

Then, the non-woven fabric was impregnated with isobutyl acetate in thesame manner as in Example 1 to give an indicator material I.

Immediately after the above indicator material was prepared, thecharacters of "End" were not recognizable. However, with the dissipationof the isobutyl acetate, the characters of "End" gradually becamerecognizable, and when the isobutyl acetate was completely dissipated(disappeared), the characters of "End" could be clearly deciphered. As aresult, the expiration of the isobutyl acetate could be more clearlyrecognized.

The above indicator material I could be set regardless of a setting siteand a setting method similarly to the indicator material I obtained inExample 1 , and the indicator material I could clearly show the degreeof dissipation of the oily substance (isobutyl acetate) which occurredwith the passage of time.

EXAMPLE 16

(Preparation of indicator material I)

A non-woven fabric provided with a resin layer on one surface wasprepared in the same manner as in Example 1 , and then a print portionof "Dissipating" was formed on a surface opposite to the resin layer,i.e., on the non-woven fabric surface by an offset printing method usinga white ink (TSP202 White, supplied by Toyo Ink Manufacturing Co., Ltd.)which was a color similar to the color of the non-woven fabric.

Then, the non-woven fabric was impregnated with isobutyl acetate in thesame manner as in Example 1 , to give an indicator material I.

Immediately after the above indicator material I was prepared, thecharacters of "Dissipating" were clearly decipherable against deep bluewhich was the color of the resin layer. With the dissipation of theisobutyl acetate, the deciphering of the characters of "Dissipating"gradually became difficult, and when the isobutyl acetate was completelydissipated (disappeared), the characters of "Dissipating" were not atall decipherable. In the above indicator material I, the dissipationstate of the isobutyl acetate could be more clearly recognized asdescribed above.

The above indicator material I could be set regardless of a setting siteand a setting method similarly to the indicator material I obtained inExample 1 , and the indicator material I could clearly show the degreeof dissipation of the oily substance (isobutyl acetate) which occurredwith the passage of time.

EXAMPLES 17-29

(Preparation of indicator material I) and Comparative Examples 5-8

Fabrics were prepared from fibers shown in Table 4, 5 or 6 amounts shownin Table 4, 5 or 6 by a wet paper making method using a cylinder papermachine, and then a wet press part, a dry part and a calender part wereproperly adjusted in each of Examples and Comparative Examples toprepare non-woven fabrics as a support. In Example 27 alone, however,the non-woven fabric was prepared by a dry method. Table 4, 5 or 6 showsthe basis weights, the non-woven fabric densities, the fiber densitiesand the non-woven fabric space volumes of these prepared non-wovenfabrics. These non-woven fabrics showed white as original color, and allthe non-woven fabrics had a refractive index of 1.7 or less.

A resin layer was formed on one surface of each of the above non-wovenfabrics in the same manner as in Example 1. Further, in Example 28,characters of "Please replace" (showing of end of dissipation) as aprint portion showing the end of dissipation were offset-printed on thesurface portion of the non-woven fabric, i.e., a surface on which theresin layer was not formed, in a tinting shade blue color having a lowerintensity than the resin layer. Further, in Example 29, not only thesame print portion as that in Example 28 was formed, but also charactersof "Dissipating" (showing of the dissipation occurring) as a printportion showing the dissipation occurring were printed on in a whitecolor which was the same as the original color of the non-woven fabric.

Then, each non-woven fabric was impregnated with empenthrin which is aliquid mothproofing agent (oily mothproofing agent volatile at roomtemperature) in an amount (cm³ /m²) equivalent to the non-woven fabricspace volume of each, whereby indicator materials I included in thepresent invention were obtained in Examples 17 to 29 and indicatormaterials not included in the present invention were obtained inComparative Examples 5 to 8. These indicator materials were determinedor evaluated for performances in the same manner as in Example 1.

                  TABLE 4    ______________________________________                                          Non-                             Density Den- woven                             of non- sity fabric                     Basis   woven   of   space    Fibers and their amounts                     weight  fabric  fiber                                          volume    for non-woven fabric                     g/m.sup.2                             g/cm.sup.3                                     g/cm.sup.3                                          (cm.sup.3 /m.sup.2)    ______________________________________    Ex. Acrylic fiber (supplied                         50      0.25  1.15 151.9    17  by Mitsubishi Rayon Co.,        Ltd.)        0.1 d *1, 3 mm, 50 parts        Heat-fusible fiber             0.93        (NBF-E, supplied by        Daiwabo)        2d, 5 mm, 50 parts    Ex. Acrylic fiber (supplied                         50      0.22  1.15 179.2    18  by Mitsubishi Rayon Co.,        Ltd.)        0.5 d, 3 mm, 50 parts        Heat-fusible fiber             0.93        (NBF-E, supplied by        Daiwabo)        2.0 d, 5 mm, 50 parts    Ex. Acrylic fiber (supplied                         45      0.20  1.15 181.7    19  by Mitsubishi Rayon Co.,        Ltd.)        1.0 d, 3 mm, 50 parts        Heat-fusible fiber             0.93        (NBF-E, supplied by        Daiwabo)        3.0 d, 5 mm, 50 parts    Ex. Polyester fiber -B*2                         45      0.20  1.38 186.0    20  (supplied by Kuraray        Co., Ltd.)        1.3 d, 5 mm, 50 parts        Heat-fusible fiber             0.93        (NBF-E, supplied by        Daiwabo)        2.0 d, 5 mm, 50 parts    Ex. Acrylic fiber (supplied                         45      0.50  1.15 48.1    21  by Mitsubishi Rayon Co.,        Ltd.)        0.1 d, 3 mm, 70 parts        Heat-fusible fiber             0.93        (NBF-E, supplied by        Daiwabo)        2.0 d, 5 mm, 30 parts    Ex. Acrylic fiber (supplied                         50      0.40  1.15 77.4    18  by Mitsubishi Rayon Co.,        Ltd.)        0.1 d, 3 mm, 60 parts        Heat-fusible fiber             0.93        (NBF-E, supplied by        Daiwabo)        2.0 d, 5 mm, 40 parts    ______________________________________     Ex. = Example     *1: The same meaning as that in note to Table 1.     *2: The same meaning as that in note to Table 1.

                  TABLE 5    ______________________________________                            Density Den- Non-woven                            of non- sity fabric                    Basis   woven   of   space    Fibers and their amounts                    weight  fabric  fiber                                         volume    for non-woven fabric                    g/m.sup.2                            g/cm.sup.3                                    g/cm.sup.3                                         (cm.sup.3 /m.sup.2)    ______________________________________    Ex. Polyester fiber-SD*3                        45      0.20  1.38 186.0    23  (supplied by Teijin        Ltd.)        1.5 d, 5 mm, 50 parts        Heat-fusible fiber            0.93        (NBF-E, supplied by        Daiwabo)        2.0 d, 5 mm, 50 parts    Ex. Acrylic fiber (supplied                        50      0.28  1.15 135.0    24  by Mitsubishi Rayon Co.,        Ltd.)        0.5 d, 3 mm, 40 parts        Heat-fusible fiber            0.93        (NBF-E, supplied by        Daiwabo)        3.0 d, 5 mm, 30 parts        Natural pulp (LBKP)           1.50        30 parts    Ex. Acrylic fiber (supplied                        40      0.15  1.15 228.2    25  by Mitsubishi Rayon Co.,        Ltd.)        1.0 d, 3 mm, 9 parts        Acrylic fiber (supplied       1.15        by Mitsubishi Rayon Co.,        Ltd.)        3.0 d, 3 mm, 41 parts        Heat-fusible fiber            0.93        (NBF-E, supplied by        Daiwabo)        3.0 d, 5 mm, 50 parts    Ex. Acrylic fiber (supplied                        30      0.09  1.15 304.5    26  by Mitsubishi Rayon Co.,        Ltd.)        1.0 d, 3 mm, 50 parts        Heat-fusible fiber            0.93        (NBF-E, supplied by        Daiwabo)        3.0 d, 5 mm, 50 parts    Ex. Polyester fiber -B*2                        40      0.1O  1.38 365.4    27  (supplied by Kuraray        Co., Ltd.)        2.0 d, 51 mm, 50 parts        Heat-fusible fiber            0.93        (NBF-E, supplied by        Daiwabo)        2.0 d, 51 mm, 50 parts        *Produced by dry method.    ______________________________________     Ex. = Example     *3: The same meaning as that in note to Table 1.     *2: The same meaning as that in note to Table 1.

                  TABLE 6    ______________________________________                                          Non-                             Density Den- woven                             of non- sity fabric                     Basis   woven   of   space    Fibers and their amounts                     weight  fabric  fiber                                          volume    for non-woven fabric                     g/m.sup.2                             g/cm.sup.3                                     g/cm.sup.3                                          (cm.sup.3 /m.sup.2)    ______________________________________    Ex.  Acrylic fiber (supplied                         50      0.30  1.15 118.6    28   by Mitsubishi Rayon Co.,         Ltd.)         0.5 d, 3 mm, 50 parts         Heat-fusible fiber            0.93         (NBF-E, supplied by         Daiwabo)         3.0 d, 5 mm, 50 parts    Ex.  Acrylic fiber (supplied                         50      0.30  1.15 118.6    29   by Mitsubishi Rayon Co.,         Ltd.)         0.5 d, 3 mm, 50 parts         Heat-fusible fiber            0.93         (NBF-E, supplied by         Daiwabo)         3.0 d, 5 mm, 50 parts    CEx. Acrylic fiber (supplied                         40      0.15  1.15 228.2    5    by Mitsubishi Rayon Co.,         Ltd.)         3.0 d, 3 mm, 80 parts         Heat-fusible fiber            0.93         (NBF-E, supplied by         Daiwabo)         3.0 d, 5 mm, 20 parts    CEx. Polyester fiber -B*2                         40      0.15  1.38 232.0    6    (supplied by Kuraray         Co., Ltd.)         3.0 d, 5 mm, 70 parts         Heat-fusible fiber            0.93         (NBF-E, supplied by         Daiwabo)         3.0 d, 5 mm, 30 parts    CEx. Acrylic fiber (supplied                         50      0.33  1.15 103.4    7    by Mitsubishi Rayon Co.,         Ltd.)         0.1 d, 3 mm, 50 parts         Heat-fusible fiber            0.93         (NBF-E, supplied by         Daiwabo)         2.0 d, 5 mm, 50 parts         *No resin layer was         formed.    CEx. No support of non-woven                         --      --    --   --    8    fabric was provided, and         a resin layer alone was         used.         The resin amount was         adjusted to 50 g/m.sup.2.    ______________________________________     Ex. = Example, CEx. = Comparative Example     *2: The same meaning as that in note to Table 1.

The indicator materials of Examples 17 to 29 and Comparative Examples 5to 8 shown in Table 4, 5 or 6 were determined or evaluated forvisibility of resin, capability of masking resin, capability of shiftingin showing and capacity to support oily substance, and Table 7 shows theresults. Those found in the determination or evaluation of the abovecharacteristics are shown in the column of Remarks.

                  TABLE 7    ______________________________________              Capa-   Capa-    Visi-     bility of                      bility of                              Capacity    bility of masking shifting                              to hold    resin     resin   in      oily    layer     layer   showing substance                                     Remarks    ______________________________________    Ex. 17          A       A       A     A      --    Ex. 18          A       A       A     A      --    Ex. 19          A       B       A     B      --    Ex. 20          A       B       A     B      --    Ex. 21          A       A       A     A      Shorter than a                                       desired time                                       length of                                       dissipation    Ex. 22          A       A       A     A      --    Ex. 23          C       B       C     B      --    Ex. 24          C       A       C     A      --    Ex. 25          A       C       C     C      --    Ex. 26          A       C       C     D      --    Ex. 27          A       C       D     D      As compared with                                       non-woven fabric                                       prepared by wet                                       method, the                                       formation was                                       poor, and the                                       evaluation                                       varied.    Ex. 28          A       A       A     A      Showing of end of                                       dissipation was                                       confirmed by                                       disappearance of                                       empenthrin.    Ex. 29          A       A       A     A      The end of                                       dissipation was                                       confirmed by                                       disappearance of                                       showing of                                       dissipating                                       based on the                                       disappearance of                                       empenthrin.    CEx. 5          A       D       D     E      --    CEx. 6          A       D       D     E      --    CEx. 7          E       E       E     A      Since no resin                                       layer was                                       formed, there                                       was no color                                       change.    CEx. 8          E       E       E     E      Could not be                                       impregnated with                                       empenthrin.    ______________________________________

The above indicator materials I obtained in Examples 17 to 29 could beset regardless of a setting site and a setting method similarly to theindicator material I obtained in Example 1, and these indicatormaterials I could clearly show the degree of dissipation of the oilysubstance (isobutyl acetate) which occurred with the passage of time.

EXAMPLE 30

(Preparation of indicator material II)

A non-woven fabric as a support was prepared from 50 parts by weight ofan acrylic fiber (supplied by Mitsubishi Rayon Co., Ltd., 0.5 d, 3 mm)and 50 parts by weight of a heat-fusible fiber (NBF-E, supplied byDaiwabo, 3d, 5 mm) by a wet paper making method using a cylinder papermachine. The prepared non-woven fabric had a basis weight of 50 g/m² anda density of 0.3 g/cm³.

About a half of the surface of the above non-woven fabric was pressedwith a press roll to increase the density of that portion, whereby ahigh-density portion and a low-density portion were formed in thenon-woven fabric. The high-density portion formed by the above pressinghad a density of 0.5 g/cm and the low-density portion (portion notpressed) had a density of 0.3 g/cm³. The non-woven fabric showed theoriginal color of white.

A resin layer was formed on one surface of the above non-woven fabric inthe same manner as in Example 1 . FIG. 1 shows a perspective view of anon-woven fabric-resin laminate 1 obtained above. In said Figure, thenon-woven fabric-resin laminate 1 was formed of the resin layer 2 andthe non-woven fabric 3, and the non-woven fabric 3 had the high-densityportion 3a and the low-density portion 3b.

The non-woven fabric 3 of the above-prepared non-woven fabric-resinlaminate 1 was impregnated with isobutyl acetate in the same manner asin Example 1 to give an indicator material II. FIG. 2 shows aperspective view of the indicator material II. In the indicator material11 in FIG. 2, the non-woven fabric 3 had a high-density portion 3c and alow-density portion 3d both impregnated with the oily substance. Throughboth the high-density portion 3c and the low-density portion 3d, thedeep blue color of the resin layer 2 could be visually recognized fromthe side of the non-woven fabric 3 as a support.

When the above indicator material 11 was allowed to stand horizontallyin a room, the low-density portion 3d of the non-woven fabric 3 alteredfrom deep blue to blue with the dissipation of the isobutyl acetate,while the high-density portion 3c of the non-woven fabric 3 kept onshowing deep blue, as shown in FIG. 3. When the indicator material wasallowed to stand further, the low-density portion 3d of the non-wovenfabric 3 altered from blue to light blue, and on the other hand, thehigh-density portion 3c of the non-woven fabric 3 altered from deep blueto blue. When the indicator material was further allowed to stand, thelow-density portion 3d of the non-woven fabric 3 altered from light blueto white, and the dissipation of the isobutyl acetate from that portionnearly came to and end. On the other hand, the high-density portion 3cof the non-woven fabric 3 altered from blue to light blue. When thearoma of the isobutyl acetate disappeared at a final step, the color ofentire surface of the non-woven fabric 3 altered to the original colorof white.

Further, when the indicator material 11 was slantly placed or suspendedperpendicularly, it was found that the color change of the high-densityportion 3c and the color change of the low-density portion 3d took placeone after the other as described above.

As described above, in the above indicator material 11, the stepwisecolor change from blue to white through light blue took place in a lefthalf and a right half of the non-woven fabric 3 one after the other, sothat the degrees of color changes could be confirmed on the basis ofcomparisons, and the degree of dissipation of the oily substance(isobutyl acetate) could be clearly shown. Further, the above indicatormaterial 11 could be set regardless of a setting site and a settingmethod.

EXAMPLE 31

(Preparation of indicator material II)

A non-woven fabric-resin laminate was prepared in the same manner as inExample 30, and then, by an offset printing method, a print portion ofcharacters of "Replace" was formed on the high-density portion of thenon-woven fabric constituting the above non-woven fabric-resin laminatein a light blue color which was similar to, but had a lower intensitythan, the color of the resin layer. And, a print portion of charactersof "in use" was formed on the low-density portion in a deep blue colorby an offset printing method. Then, the above non-woven fabric wasimpregnated with isobutyl acetate in the same manner as in Example 1 togive an indicator material II.

At a stage where the impregnation with isobutyl acetate was completed,the above-prepared indicator material II was in a state in which thedeep blue color of the resin layer was clearly visually recognizablefrom the non-woven fabric layer side, the characters of "in use" werenot visually recognizable since they were of a color similar to that ofthe resin layer, and further, the characters of "Replace" were notvisually recognizable, either, since they were in light blue. When theindicator material II was horizontally placed in a room, the low-densityportion of the non-woven fabric altered from deep blue to blue with thedissipation of the isobutyl acetate, and the characters of "In use"became recognizable. At this stage, the high-density portion of thenon-woven fabric kept on showing a deep blue color, and the charactersof "Replace" were in a state in which they were not visually recognized.Then, when a time further passed, the low-density portion of thenon-woven fabric altered from blue to light blue, and the high-densityportion of the non-woven fabric altered from deep blue to blue. At thisstage, the characters of "Replace" were still in a state in which theywere not visually recognized. Thereafter, when a time further passed,the low-density portion of the non-woven fabric altered from light blueto white, the original color of the non-woven fabric, and on the otherhand, the high-density portion of the non-woven fabric altered from blueto light blue. Then, when the isobutyl acetate disappeared at a finalstep, the color of entire surface of the non-woven fabric altered towhite, the original color of the non-woven fabric so that the charactersof "In use" in light blue and the characters of "Replace" in deep bluecame into a state where they were recognizable.

Further, when the indicator material II was slantly placed orperpendicularly suspended, it was found that the color change of thehigh-density portion and the color change of the low-density portiontook place one after the other as described above.

As described above, in the above indicator material II, the stepwisecolor change from blue to white through light blue took place in a lefthalf and a right half of the non-woven fabric one after the other, sothat the degrees of color changes could be confirmed on the basis ofcomparisons, and the degree of dissipation of the oily substance(isobutyl acetate) could be clearly shown. Further, since the charactersof "Replace" were not shown before the effect of the aromatic agent(isobutyl acetate) lost its effect, the exchange time can be clearlyrecognized. Further, the above indicator material II could be setregardless of a setting site and a setting method.

Example 32

(Preparation of indicator material II)

A non-woven fabric-resin laminate was prepared in the same manner as inExample 30, and then, by an offset printing method, a print portion ofcharacters of "Replace" was formed on the high-density portion of thenon-woven fabric constituting the above non-woven fabric-resin laminatein a light blue color. And, a print portion of characters of "in use"was formed on the low-density portion in a white color by an offsetprinting method. Then, the above non-woven fabric was impregnated withisobutyl acetate in the same manner as in Example 1 to give an indicatormaterial II.

In the above-prepared indicator material II, at a stage where theimpregnation with isobutyl acetate was completed, the deep blue color ofthe resin layer was clearly visually recognizable from the non-wovenfabric layer side, the characters of "in use" were visually recognizablesince they were in white. Further, the characters of "Replace" were notvisually recognizable, since they were in light blue. When the indicatormaterial II was horizontally placed in a room, the low-density portionof the non-woven fabric altered from deep blue to blue with thedissipation of the isobutyl acetate. At this stage, the characters of"In use" were also in a recognizable state. On the other hand, thehigh-density portion of the non-woven fabric kept on showing a deep bluecolor, and the characters of "Replace" were in a state in which theywere not visually recognized. Then, when a time further passed, thelow-density portion of the non-woven fabric altered from blue to lightblue, and the high-density portion of the non-woven fabric altered fromdeep blue to blue. At this stage, the characters of "Replace" were stillin a state in which they were not visually recognized. Thereafter, whena time further passed, the low-density portion of the non-woven fabricaltered from light blue to white, so that the characters of "In use"became indecipherable. On the other hand, the high-density portion ofthe non-woven fabric altered from blue to light blue. Then, when theisobutyl acetate disappeared at a final step, the color of entiresurface of the non-woven fabric altered to white, and the characters of"Replace" came into a state where they were recognizable.

Further, when the indicator material II was slantly placed orperpendicularly suspended, it was found that the color change of thehigh-density portion and the color change of the low-density portiontook place one after the other as described above.

As described above, in the above indicator material II, the stepwisecolor change from blue to white through light blue took place in a lefthalf and a right half of the non-woven fabric one after the other, sothat the degrees of color changes could be confirmed on the basis ofcomparisons, and the degree of dissipation of the oily substance(isobutyl acetate) could be clearly shown. Further, since the charactersof "Replace" were not shown before the effect of the aromatic agent(isobutyl acetate) lost its effect, and since the characters of "In use"disappeared when the aromatic agent (isobutyl acetate) lost its effect,the exchange time could be clearly shown. Further, the above indicatormaterial II could be set regardless of a setting site and a settingmethod.

EXAMPLE 33

(Preparation of indicator material II)

A non-woven fabric as a support was prepared from 50 parts by weight ofan acrylic resin (supplied by Mitsubishi Rayon Co., Ltd., 2d, 3 mm) and50 parts by weight of a heat-fusible fiber (NBF-E, supplied by Daiwabo,3 d, 5 mm) by a wet paper making method using an inclined paper machine.The prepared non-woven fabric had a basis weight of 50 g/m² and adensity of 0.1 g/cm³.

About a half of the surface of the above non-woven fabric was pressedwith a press roll to increase the density of that portion, whereby ahigh-density portion and a low-density portion were formed in thenon-woven fabric. The high-density portion formed by the above pressinghad a density of 0.3 g/cm³ and the low-density portion (portion notpressed) had a density of 0.1 g/cm³. The non-woven fabric showed theoriginal color of white.

A resin layer was formed on one surface of the above non-woven fabric inthe same manner as in Example 1 to prepare a non-woven fabric-resinlaminate. Then, the non-woven fabric of the non-woven fabric-resinlaminate was impregnated with isobutyl acetate in the same manner as inExample 1 to give an indicator material II.

The above-obtained indicator material II was determined or evaluated forperformances as an indicator material to show that, like the indicatormaterial II obtained in Example 30, it could be set regardless of asetting site and a setting method and that it could clearly show notonly the time of expiration of the oily substance (isobutyl acetate) butalso the degree of dissipation of the oily substance (isobutyl acetate)with the passage of time.

EXAMPLE 34

(Preparation of indicator material II)

A non-woven fabric-resin laminate was prepared in the same manner as inExample 33, and then, the non-woven fabric of the non-woven fabric-resinlaminate was impregnated with empenthrin which was a liquid mothproofingagent (oily mothproofing agent volatile at room temperature) in the samemanner as in Example 1 , to give an indicator material II.

The above-obtained indicator material II was determined or evaluated forperformances as an indicator material to show that, like the indicatormaterial II obtained in Example 30, it could be set regardless of asetting site and a setting method and that it could clearly show notonly the time of expiration of the oily substance (empenthrin) but alsothe degree of dissipation of the oily substance (empenthrin) with thepassage of time.

EXAMPLE 35

A non-woven fabric as a support was prepared from 50 parts by weight ofan acrylic resin (supplied by Mitsubishi Rayon Co., Ltd., 3d, 3 mm) and50 parts by weight of a heat-fusible fiber (NBF-E, supplied by Daiwabo,3d, 5 mm) in the same manner as in Example 33. The prepared non-wovenfabric had a basis weight of 50 g/m².

The portion, which was nearly a central portion of the non-woven fabricwhen viewed from the above, was circularly and perpendicularly pressedto increase the density of that portion, whereby a high-density portionand a low-density portion were formed in the non-woven fabric. Thehigh-density portion formed by the above pressing had a density of 0.3g/cm³ and the low-density portion (portion not pressed) had a density of0.09 g/cm³. The non-woven fabric showed the original color of white.

A resin layer was formed on one surface of the above non-woven fabric inthe same manner as in Example 1 to prepare a non-woven fabric-resinlaminate. Then, the non-woven fabric of the non-woven fabric-resinlaminate was impregnated with 100 g/m² of a thyme oil (one oilymothproofing agent) as an oily substance volatile at room temperature inthe same manner as in Example 1 to give an indicator material II.

As shown in FIG. 4, in the above indicator material 15, the non-wovenfabric 16 had the high-density portion 16a and the low-density portion16b both impregnated with the oily substance. The high-density portion16a of the non-woven fabric 16 showed a circular form when viewed fromabove, and the high-density portion 16 was located nearly in the centralportion of the non-woven fabric 16 when viewed from above. On the otherhand, the low-density portion 16b of the non-woven fabric 16 was locatedaround the high-density portion 16a, and the low-density portion 16bsurrounded the high-density portion 16a. Through both the high-densityportion 16a and the low-density portion 16b, the deep blue color of theresin layer 17 formed on one surface of the non-woven fabric 16 could beclearly visually recognized from the side of the non-woven fabric 16 asa support.

In the above indicator material 15, the thyme oil (not shown in FIG. 4)used for the impregnation of the non-woven fabric 16 were dissipatedfrom both the high-density portion 16a and the low-density portion 16b,while the thyme oil with which the low-density portion 16b had beenimpregnated shifted into the high-density portion 16a spontaneously andeffectively with the dissipation of the thyme oil from the high-densityportion 16a. Therefore, when the observation was made toward the resinlayer 17 side from the non-woven fabric 16 side, the high-densityportion 16a was visually recognized in deep blue for a long period oftime. Further, even after the low-density portion 16b became visuallyrecognized in white after the thyme oil in the low-density portion 16bdisappeared (although the color of the resin layer 17 was visuallyrecognized in a light color), the high-density portion 16a was visuallyrecognized in deep blue, while the high-density portion 16a rapidlyaltered to white.

It was found that the color change of the high-density portion 16a andthe color change of the low-density portion 16b took place one after theother as described above even if the above indicator material 15 washorizontally placed, slantly placed or perpendicularly suspended. Whenthe indicator material 15 was perpendicularly suspended, however,puddles of the oily substance (thyme oil) formed to some extent.

In the above indicator material 15, the degree of color change with thedissipation of the oily substance (thyme oil) differed to a great extentbetween the high-density portion 16a and the low-density portion 16b asdescribed above, and the indicator material 15 could more clearly showthe degree of the oily substance (thyme oil). Further, the indicatormaterial 15 could be used regardless of a setting site and a settingmethod.

As explained in detail in Examples and Comparative Examples, theindicator material I and the indicator material II of the presentinvention can clearly show not only the time of expiration of the oilysubstance but also the degree of dissipation of the oily substance whichoccurs with the passage of time, regardless of a setting site and asetting method.

Further, the indicator material using, as a support, the non-wovenfabric containing a fine-denier fiber having a size of 2 denier or lesscan contain a relatively large amount of the oily substance.

We claim:
 1. An indicator material provided by forming a resin layer having a surface partly or wholly colored on one surface of a support formed of a non-woven fabric comprising a fine-denier fiber having a size of 2 denier or less said support and having a low refractive index to light, and impregnating the support with an oily substance volatile at ambient temperature or higher temperature, wherein the resin layer observed from the support side is shifted from a visible state to a support-masked state by the dissipation of the oily substance which occurs with the passage of time.
 2. The indicator material of claim 1, wherein the non-woven fabric as a support contains 9 to 100% by weight of the fine-denier fiber having a size of 2 denier or less.
 3. The indicator material of claim 1, wherein the non-woven fabric as a support contains 20 to 100% by weight of the fine-denier fiber having a size of 2 denier or less.
 4. The indicator material of claim 1, wherein the non-woven fabric as a support contains a fine-denier fiber having a size of 1 denier or less.
 5. The indicator material of claim 1, wherein the non-woven fabric as a support has a density of 0.1 to 0.5 g/cm³.
 6. The indicator material of claim 1, wherein the non-woven fabric as a support has a non-woven fabric space volume of at least 50 cm³ /m².
 7. The indicator material of claim 1, wherein the non-woven fabric as a support is a non-woven fabric prepared by a wet paper making method.
 8. The indicator material of claim 1, wherein the non-woven fabric as a support contains a heat-fusible fiber.
 9. The indicator material of claim 1, wherein the resin layer is a thermoplastic resin coating whose surface is partly or wholly colored.
 10. The indicator material of claim 1, wherein the resin layer has a surface partly or wholly colored by a printing method.
 11. The indicator material of claim 1, wherein the indicator material has a print portion showing the termination of dissipation of the oily substance, which print portion is formed on a surface of the non-woven fabric opposite to the surface provided with the resin layer, in a color which has a lower intensity than, and is similar to, a colored portion of the resin layer.
 12. The indicator material of claim 1, wherein the indicator material has a print portion showing upon dissipation of the oily substance, which is formed on a surface opposite to the surface provided with the resin layer, in a color similar to a color of the non-woven fabric.
 13. The indicator material of claim 1, 11 or 12, wherein the oily substance is an oily mothproofing agent or insecticide volatile at ambient temperature or higher temperature.
 14. The indicator material of claim 13, wherein the oily mothproofing agent or insecticide is an evaporable pyrethroid-containing insecticide.
 15. An indicator material prepared by forming a resin layer having a surface partly or wholly colored on one surface of a support formed of a non-woven fabric having a partly altered density and having a low refractive index to light, and impregnating the support with an oily substance volatile at ambient temperature or higher temperature, wherein the resin layer observed from the support side is shifted from a visible state to a support-masked state by the dissipation of the oily substance which occurs with the passage of time.
 16. The indicator material of claim 15, wherein a portion having a relatively high density is surrounded by a portion having a relatively low density in the non-woven fabric as a support.
 17. The indicator material of claim 15, wherein the non-woven fabric as a support is a non-woven fabric having a partly altered density obtained by partly pressing a non-woven fabric having a substantially uniform density.
 18. The indicator material of claim 15, wherein the non-woven fabric as a support contains a fine-denier fiber having a size of 2 denier or less.
 19. The indicator material of claim 15, wherein the non-woven fabric as a support contains 9 to 100% by weight of a fine-denier fiber having a size of 2 denier or less.
 20. The indicator material of claim 15, wherein the non-woven fabric as a support contains 20 to 100% by weight of a fine-denier fiber having a size of 2 denier or less.
 21. The indicator material of claim 15, wherein the non-woven fabric as a support contains a fine-denier fiber having a size of 1 denier or less.
 22. The indicator material of claim 15, wherein the non-woven fabric as a support contains a heat-fusible fiber.
 23. The indicator material of claim 15, wherein the non-woven fabric as a support is a non-woven fabric obtained by partly altering a density of a non-woven fabric prepared by a wet paper making method.
 24. The indicator material of claim 15, wherein the resin layer is a thermoplastic resin coating partly or wholly colored.
 25. The indicator material of claim 15, wherein the resin layer has a surface partly or wholly colored by a printing method.
 26. The indicator material of claim 15, wherein a print portion showing the termination of dissipation of the oily substance is formed on a high-density portion on a surface opposite to the surface provided with the resin layer, in a color which has a lower intensity than, and is similar to, a colored portion of the resin layer.
 27. The indicator material of claim 15, wherein a print portion showing upon dissipation of the oily substance is formed on a surface on the non-woven fabric opposite to the surface provided with the resin layer, in a color which has a higher intensity than or an intensity equivalent to, and is similar to, a colored portion of the resin layer, or in a color similar to the non-woven fabric.
 28. The indicator material of claim 27, wherein the print portion is formed on a low-density portion of the non-woven fabric.
 29. The indicator material of claim 15, 26 or 27, wherein the oily substance is an oily mothproofing agent or insecticide volatile at ambient temperature or higher temperature.
 30. The indicator material of claim 29, wherein the oily mothproofing agent or insecticide is an evaporable pyrethroid-containing insecticide.
 31. The indicator material claim 1, wherein the non-woven fabric has a partly altered density. 